This invention relates to utilization of content having digital rights management and co-utilization of the content through a network.
As music recording and playing equipment having content such as pictures and videos owing to popularization of digital video cameras and equipped with a hard disk has become spread, contents such as music and broadcasting contents of digital broadcasting can now be stored easily at home. A hard disk recorder that has replaced a VCR (Video Cassette Recorder) can store not only the broadcasting content but also various kinds of contents described above.
On the other hand, movement and copy of the content between these kinds of equipment have been made by utilizing storage media and by connecting dedicated lines such as USB (Universal Serial Bus) networks, IEEE1394 or the like. Since each of equipment has the IP network function, it has become popular to download the content from the Internet. Therefore, reference to the contents stored in each of equipment has often been required.
With the technical background described above, a security function that permits only authentic users to utilize the contents (reference, transfer, copy, etc) but prevents utilization of the contents by unauthentic users has been accomplished or proposed because degradation of image quality is less in the case of the digital content.
JP-A-2003-273861 contemplates to achieve digital rights management by a system that stores an encrypted file and an execution conformation processing program in a storage medium on the basis of a master file containing encrypted contents in a server device, acquires a content utilization permission from a client device (portable device) to the server device when a plurality of client devices utilizes the encrypted file through the storage medium, acquires then a cipher key of the content and plays the content.
However, the technology described above decides utilizability of the content when the content is utilized but does not judge it at the time of distribution/transfer of the content. Therefore, the technology involves the problem that it is not suitable for content utilization for real-time distribution/transfer of the contents stored in a server device through a network. The technology cannot either transfer an optimam content corresponding to various digital rights management rules or kinds.
Still another problem of the technology is that the content stored in the own device and the content looked up through the network cannot be managed by the same utilization system.